#include <REGX52.H>
void Delay1ms(unsigned int xms)		//@11.0592MHz
{
	unsigned char i, j;
	while(xms)
	{
			i = 2;
			j = 199;
			do
			{
				while (--j);
			} while (--i);	
			xms--;
	}
}

void main()
{  //????,?????
		while(1)
		{
				if(P3_1==0)
				{
					Delay1ms(20); //?????
					while(P3_1==0);
					Delay1ms(20); //?????
					
					P2_0=~P2_0; //??,???,???
				}
		}
}
